$OpenBSD: patch-gtk2_ardour_tempo_lines_h,v 1.1 2017/05/25 09:02:05 espie Exp $
allocator *has to match*

Index: gtk2_ardour/tempo_lines.h
--- gtk2_ardour/tempo_lines.h.orig
+++ gtk2_ardour/tempo_lines.h
@@ -45,7 +45,7 @@ class TempoLines { (public)
 	void hide();
 
 private:
-#ifdef GTKOSX
+#if defined(GTKOSX) || defined(__clang__)
 	typedef std::map<double, ArdourCanvas::SimpleLine*, std::less<double> > Lines;
 #else
 	typedef std::map<double, ArdourCanvas::SimpleLine*, std::less<double>, MapAllocator> Lines;
